There are known in the art a number of pharmacologicall active 1-piperazinecarboxamides which are substituted in the 4-position with an unsubstituted or substituted arylalkyl side chain or a functional derivative thereof. Such compounds may be found in the following references: Japan Kokai No. 76 08, 283 British Pat. No. 2,037,745.
There are also known in the art a number of butyrophenones derived from 1-acylpiperazine. They are reported to display a central depressant activity.
U.S. Pat. No. 3,000,892 describes as having central depressant and hypnotic activity compounds of formula ##STR2## wherein Ar is a member of the class consisting of phenyl, methoxyphenyl, halophenyl, dimethoxyphenyl, and trimethoxyphenyl, and where Q is hydrogen, methoxy or halogen.
In the article "1-.vertline.3-(4-Fluorobenzoyl)propyl-.vertline.4-acylpiperazines and some related compounds" by M. Rajsner et al. in Collect. Czech. Chem. Commun. 1975, 40(4), 1218-30, among the compounds described are those having the general formula ##STR3## wherein R is OEt, Et, NH.sub.2 and N(CH.sub.3).sub.2. The compounds are reported to show only a slight central depressant activity which is apparent only in high doses.
Among the compounds disclosed by Swedish Pat. No. 350,497 are compounds under the general formula (B) wherein R is OR', where R' represents an alkyl group having from 1 to 4 carbon atoms, a cyclic hydrocarbon radical, e.g. cyclohexyl or an arylalkyl group, e.g. benzyl. The compounds have for example neuroleptic properties.
The compounds of the present invention differ from the foregoing essentially by being 1-piperazinecarboxamides, having particular substituent groups in the 4-position, or by having a special combination of substituent groups in the 4-position and on the nitrogen in the amide function.
The pharmacological properties which clearly distinguish the compounds of the present invention from what is known in the art are described under the heading "Pharmacological Properties".